Device for fluid blocking in a pipe line

ABSTRACT

The invention relates to a device for blocking a flow in a pipeline under pressure, comprising a clamp member (1) for encasing a section of the mantle surface of the pipeline and comprising a pipe socket (2) with a valve (17), switchable between an open and a closed position, and a hole-making tool (3) for producing a hole (56) in the mantle surface during sealing between the tool and the pipe socket. A blocking means (4) is adapted to be inserted through the produced hole and to expand in the pipeline for the purpose of blocking the flow in the pipeline. The blocking means consists of a body with a cross-sectional dimension which is less than the cross-sectional dimension of the hole, and a support member being guided in the pipe socket. Two sliding elements, which are carried by the body, are via the support member adjustable from the outside between an open position in which it is retracted into the body, and an expanded blocking position, in which it seals against the inner circumference of the pipeline.

TECHNICAL FIELD

The present invention relates to a device for blocking flow in apipeline in accordance with the preamble of the subsequent claim 1.

BACKGROUND OF THE INVENTION

It is known from for example SE 8605201-1 to arrange a blocking in apipeline which is under pressure. This known device comprises a bladderwhich is caused to expand in the pipeline by means of compressed air.This device has a natural upper limit regarding applications inpipelines with large dimensions and high levels of pressure.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a blocking devicewhich may be applied to pipelines with small as well as large pipelinedimensions, and low as well as high fluid pressures.

Said object is obtained by means of a device in accordance with thepresent invention, the features of which will be apparent from thesubsequent claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with certain embodiments, withreference to the annexed drawings, in which

FIGS. 1, 2 and 3 show partly sectioned views of components forming partof the device according to the invention, according to a firstembodiment,

FIG. 4 shows a cross-section of the device in a hole-making stage,

FIG. 5 shows a cross-section of the device according to FIGS. 1 to 4,prepared for the insertion of a blocking means according to theinvention,

FIG. 6 shows a corresponding view with the device according to FIGS. 1to 5 in a blocking position,

FIG. 7 shows a cross-section on a larger scale of the blocking meansalong the line VII--VII in FIG. 5, the blocking means being shown in anopen position,

FIG. 8 shows a corresponding view of the blocking means in the form of across-section along the line VIII--VIII in FIG. 6, showing a blockingposition, whereas

FIG. 9 shows a cross-section of the device along the line IX--IX in FIG.8,

FIG. 10 shows a cross-section of the remaining device after the blockingis finished,

FIG. 11 shows an alternative embodiment of a part,

FIG. 12 shows a longitudinal cross-section of a blocking means formingpart of the invention, in a second embodiment,

FIG. 13 shows a clamp member forming part of the invention, in a secondembodiment, and

FIG. 14 shows, on a larger scale, a partial sectional view of theembodiment according to FIG. 12, however somewhat modified.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The main components of the blocking device, which thus are shown in afirst embodiment in FIGS. 1 to 3, are a clamp member 1 including a pipesocket 2, a hole-making tool 3, a blocking means 4 and a driving device5 for the hole-making tool as well as the blocking device. The clampmember has inner surfaces 6, 7 of cylinder-jacket shape, adapted forsealingly surrounding a section of the pipeline, the fluid of which isto be blocked. In order to accomplish this without having to screw theclamp member on from either end of the pipeline, the clamp member isdivided into two roughly halfcylinder-shaped parts 8, 9 with flanges 10intended to be joined to each other by means of screws (see FIG. 4) andthus pressing against the outer mantle surface of the pipeline. The pipesocket 2 comprises an inner part 11 which is integrated with the clampmember 1, or more precisely its first part 9, so that the inner part 11presents a through-duct 12 with an opening 13 outwardly from the clampmember and an opening 14 inwardly towards the space 15 delimited by theclamp member.

The pipe socket 2 is divided into the inner part 11 and an outer part 16which is releasably attachable to the inner part 11 with a closing valve17 interpositioned in the partition location 18 of the inner and outerparts of the pipe socket. In this respect, the inner part 11 is providedwith a flange 19 around the opening 13, for sealingly fitting to oneflange 20 of the closing valve 17, whereas the other flange 21 of theclosing valve is intended for sealingly mounting of the outer part 16 ofthe pipe socket, more precisely at a flange 22 which surrounds an inneropening 23 of the part 16. The outer part 16 of the pipe socket alsopresents a through-duct 24, which at its outer end 25 has a tapered duct26 with an opening 27. The outer part 16 comprises sealing means in theduct 26 which, in the shown example, is an inner ring-shaped seal 28 andan outer ring-shaped seal 29 for sealingly fitting to parts of thehole-making tool 3 and also the blocking means 4, which will beexplained in greater detail below.

The outer part 16 of the pipe socket carries a support 30 for thedriving device 5, which in the shown example is a hand tool of thedrilling machine type, fitted in the support and displaceably supportedby a holding member 31, which in a conventional manner may be adjustedbetween different vertical positions by means of a rack and piniondevice. The driving device comprises an outgoing rotatable driving shaft32 with a chuck 33 for a rotatably fixed drive mounting of thehole-making tool 3 and the blocking means 4, respectively. The drivingshaft 32 of the driving device 5 is mounted coaxially in relation to thesymmetric longitudinal axle 34 of the blocking device. The support 30 isin the shown example at its lower end firmly attached to a flange 35,which is laterally directed and protrudes from the outer part 16 of thepipe socket.

At the lower section of the outer part 16 of the pipe socket 2 there isarranged a flushing valve 36 which, at certain occasions, is intended tobe opened in order to relieve the pressure on the outer part fordismounting.

The hole-making tool 3 consists of a drill bit 37 with circularlylocated sawteeth 38 for making a circular hole with a diameter whichslightly exceeds the diameter of the blocking means 4. The drill bit 37is arranged on a long drive shaft 39 of such a length that the upper end40 of the drive shaft may be fixed in the chuck 33 and the drive shaftmay extend through the pipe socket 2 and, together with the drill bit,produce a hole 41 in the pipeline 42, see FIG. 4. The drive shaft 39 mayeither be a unit, so that the hole-making tool 3 rotates as one piece bymeans of the driving device 5, or alternatively the drive shaft may bemounted in a shaft sleeve, which essentially does not rotate with theshaft, thereby sparing the sealings 28, 29.

The blocking means 4 is shown in its entirety in FIG. 3, and in greaterdetail in FIGS. 7, 8 and 9. At its lower part, the blocking means 4consists of a body which is intended to be inserted through a hole inthe pipeline, which will be described in greater detail below. A supportmember 42 extends from the body and also forms an operating part for theoperation of the blocking means. The support part 42 comprises a shaftsleeve 43 which is rotatably fixed to the body 41, through which sleevean operating through-shaft 44 extends, the upper end 45 of which isadapted to be fastened in the chuck 33 of the driving device 5. Theoperating shaft 44 extends down into the body 41 and is adapted totransmit, via a transmission gear 46, a rotary motion of the operatingshaft 44 to a reciprocating motion of two blocking sliding elements 47,48 which are guided in two slit-shaped cavities 49, 50, respectively, inthe body 41. In the shown example, the body is surrounded by an elasticcover 51 of rubber or similar, which sealingly surrounds the body as awhole but which is formed of a material which is flexible and highlyductile so that the cover allows a protruding motion of the two slidingelements 47, 48, which is shown in FIG. 8. In the shown example, thetransmission gear 46 is formed by a gear 52 on the operating shaft 44and two smaller gears 53, 54 for gear reduction of the motion, and agear rack 55 on the inside of each one of the sliding elements 47, 48.The gears 53, 54 mesh with the gear 52 and also with both of the rackgears. As is apparent from FIGS. 7 and 8, rotation in the direction ofthe arrows leads to a linear protruding motion of the two slidingelements.

Regarding the contour shape of the blocking means, it is apparent fromFIGS. 7 and 8 that the cross-section shape of the body 41, i.e. in across-section across the longitudinal axle of the operating shaft 44,i.e. in one of its radial planes, comprises an outer contour which issurrounded by a circle which corresponds to the diameter of the drillbit, i.e. diameter of the produced hole 56. The circumference of theproduced hole is indicated by a dot-dash line 56 in FIG. 7. In practice,the diameter of the hole is of course chosen with a certain clearance inrelation to the diameter of the body.

As is apparent from FIG. 4, the sliding elements 47, 48 comprisearc-shaped outer edges 58, 59 with a radius of curvature whichcorresponds to the radius of curvature of the inner circumference 60 ofthe pipeline 57 in question. Furthermore, in its lower end 61 the body41 comprises a cylinder mantle shape which follows this contour shapeand which is rounded off so that in the protruding, expanded positionsof the sliding elements shown in FIG. 9, the body together with thesliding elements completely fill the cross-section of the pipeline,thereby blocking the flow through the pipeline. By means of the elasticcover 51, a good contact with the inner circumference of the pipeline isobtained by adapting to minor irregularities and deviations from theideal shape.

The blocking device according to the invention which is described aboveis used in the following manner, for blocking of fluid, i.e. a liquid ora gas, in a pipeline under pressure. Demand for blocking under pressuremay exist for various situations, such as accidents, for example afracture of the pipeline, or during construction work where also certainclosing valves are concerned so that a blocking must be made upstream ofthe first valve. At the section where a blocking must be carried out,the clamp 1 is mounted, the two parts 8, 9 of which are connected fromopposite directions by means of a screw joint 62 through the flangeholes 63. Advantageously, the part 9 is provided with some kind ofsealing section in the area around the inner opening 14 of the pipesocket 2, which may be accomplished by means of a sealing layer in themantle surface or alternatively in the form of a sealing ring around theopening. Thereafter, the closing valve 17 is mounted, which for examplemay be a sliding valve, a ball valve or the like. Since one part 9 ofthe clamp 1, the inner part 11 of the pipe socket 2 and the closingvalve 17 are always intended to be firmly connected to one another, theclosing valve may be mounted from the start, which may involve a gain intime.

The next step is the hole-making operation. To this end, the hole-makingtool 3 is inserted from below in the outer part 16 of the pipe socket,which in this regard stands free from the closing valve 17 and forexample lies so that the driving shaft 39 may be inserted from insidethrough the duct 26 and with its end 40 may be rotatably fixed to thechuck 33 of the driving device. In this regard, provision must be madefor the driving device to be in such a withdrawn position, see FIG. 4,that the drill bit 37 is withdrawn into the upper, outer part 16 of thepipe socket. Thereafter, the upper part 16 of the pipe socket 2 ismounted to the closing valve 17, flange against flange, by means of ascrew joint 64. Between the flanges of the valve and the inner and outerparts, respectively, of the pipe socket there are arranged washers inorder to obtain a proper sealing. In this regard, the closing valve 17must be maintained open by operating its operating means 65, in theshown example by turning of a wheel, so that the valve 17 presents anopening of sufficient dimensions for allowing the hole-making tool andthe drill bit to be inserted down through the valve and towards themantle surface of the pipeline 57 in the area that faces the opening 14.The axial movement of the hole-making tool is provided by displacing thedriving device 5 in a direction towards the pipeline along the support30. By means of the holding member 31 for the driving device with itsoperating device 66, the drill bit 37 is applied with a certain forceagainst the mantle surface of the pipeline, thereby activating thedriving device 5 for rotation of the drive shaft 39 until the circularhole 56 has been formed. In a manner which is known, the cut off section37 may remain in the drill bit and be carried away in a return motionduring which the driving device 5 is raised, so that the drill bitresumes the retracted position shown in FIG. 4. Due to the fact that thedriving shaft 39 or, where appropriate, its driving shaft sleeve issealingly fitted against the seals 28, 29 of the pipe socket, wherebythe flushing valve 36 is also maintained closed, the pipe socket 2 stillforms a closed space when the closing valve 17 is held open. Both theinner part 11 and the outer part 16 of the pipe socket are thusmaintained under the same fluid pressure as in the pipeline 57.Depending on the degree of sealing a fluid may, to a high or a lowdegree, flow into the space 24 in the outer part 16 of the pipe socket,but is prevented to a varying degree by the quantity of air whichremains in the space and which is compressed by the fluid pressure. Inpractice, it is not always necessary to obtain a 100% sealing, forexample in the channel 27 around the shaft 39.

After the hole-making tool 3 has been retracted, the operator ensuresthat the closing valve 17 is completely shut. Thereafter, the flushingvalve 36 is suitably opened for relieving of the pressure in the spacein the outer part 16 of the pipe socket. This may thereafter once againbe removed, whereby a small amount of fluid pours out. The hole-makingtool 3 is disconnected from the chuck 33 and is pulled out from theouter part 16 of the pipe socket and is replaced by the blocking means42, which is inserted in the same way as the hole-making tool 3 in thepart 16 so that its drive shaft 42 is inserted from the inside throughthe duct 27 and is mounted in the chuck 33 with the end part 45 of thedrive shaft.

The outer end 16 of the pipe socket is thereafter once more mounted tothe outer flange 21 of the closing valve 17 by means of the screw joint64, see FIG. 5. Devices which are not shown make sure that the blockingmeans 4 reaches, and is maintained in, a predetermined fixed rotaryposition so that the blocking means is expanded during the closingmovement in a direction across the longitudinal direction of thepipeline 57. This fixing of the position may be carried out by a controloutside or inside of the pipe socket 2. It is ensured that the flushingvalve 36 once again is kept closed and the closing valve 17 is keptopen. The inner parts of the valve are shown completely schematically ina partly cut section in FIG. 5 in order to illustrate the completelyopen duct within the pipeline. Thereafter, the blocking means 4 isinserted down through the valve 17, through the duct 12, the producedhole 56 in the pipeline and into this until the body of the blockingmeans with its lower part 61 is in contact with the bottom of the lineor its inner circumference opposite the produced hole 56. In a way whichcorresponds to the making of the hole, the pipe socket forms togetherwith the inner parts of the clamp and the pipeline a closed unit, theinner parts of which are essentially sealed from the environment.

When the blocking means is fitted in the fluid line and its rotaryposition has been assured by a position control and some kind ofholding, for example by the operating sleeve 43 or the body 41, thedriving device 5 is activated for rotation of the operating shaft 44.Via the transmission gearing 46, the blocking sliding elements 47, 48are forced to move in opposite directions, whereby the elastic cover 51is streched as shown in FIG. 8 until the blocking sliding elements withtheir arc-shaped circumferences 58, 59 sealingly fit against the innercircumference of the pipeline, whereby a fluid blocking takes place inthe present zone of the pipeline, see FIG. 6. The blocking slidingelements are arranged together with the body 41 around the entire innercircumference of the pipeline in such a way that a complete fluidblocking occurs against a continued flow downstream from the blockingposition. When the blocking device is placed in the blocking position,the body and the elastic cover 51 assure also that a sealing isaccomplished around the hole 56 so that any flow via the hole does notoccur. As is apparent from FIG. 6, this sealing is assured due to thefact that the body 41 with its cover 51 protrudes out of the hole 56with a cylindrical part 69.

By blocking the flow in the fluid pipeline 57, the pipeline systemdownstream of the blocking position may be emptied from fluid andnecessary work may be carried out. When the work is finished, theblocking means is activated for release of fluid, which takes place byreversing the rotary direction of the operating shaft 44, which may becarried out by means of a built-in reverse gear in the driving device 5or by a not shown gear in the operation shaft 42. In this manner, theblocking sliding elements 47, 48 are retracted from their positionsshown in FIG. 8 to their positions shown in FIG. 7. The body 41 of theblocking means has thereby gained such dimensions that the blockingmeans may be inserted through the opening 56 by turning the lever 66 andthereby raising the driving device 5 and the operating shaft 42, untilthe body 41 has passed the closing valve 17 and been placed in theposition shown in FIG. 5.

In this regard, the closing valve 17 is readjusted by activating theoperating means 65 to the closed position, after which the flushingvalve 36 once again is opened in order to unload the pressure in theouter part 16 of the pipe socket, which thereafter may be releasedthrough loosening of the screw joint 64.

In a final stage for restoring after the blocking is finished, a coverplate 67 is fixed to the outer flange 21 of the valve, and is screwed onby means of a screw joint 68, preferably with an intermediate washereven if the valve 17 is assumed to be tight.

FIGS. 11, 12 and 13 show elements forming part of the device accordingto the invention in a second embodiment. FIG. 11 shows a partly brokenview of a hole-making tool 70 in the form of a drill bit 71 with adiameter which is less than the drill bit according to FIG. 2 and whichis intended to produce a second hole, which will be described in greaterdetail below. On the same shaft 72, there is also arranged a deburringtool 73 in the form of a grinding wheel with a diameter which is adaptedto the diameter of the hole 56 in order to make possible a deburring,especially of the edge of the hole towards the inner parts of the pipe57.

By means of the deburring, there is a smaller risk that the elasticcover 51 on the blocking means is damaged against burred edges which areformed when the hole is made.

FIG. 12 shows the blocking means, here indicated by 74, in a secondembodiment which essentially corresponds to the first embodiment, whichmeans that only the differing parts will be described here. In thisexample, the lower part of the blocking means 74 comprises support meansin the form of a stud 76 which is downwardly protruding from its fixedbase portion 75 and which extends through a hole in the elastic cover51. The stud 76 is adapted to be inserted into a hole 77 in the pipeline57, which is indicated with dot-dash lines in FIG. 12. This hole 77 isformed by means of the drill bit 71, centrally in relation to thesymmetry line 34 and opposite the hole 56 with a smaller diameter thanthe hole 56, in order to make possible that the hole-making toolaccording to FIG. 11 may be inserted through the hole 56 which was firstproduced. The conical shape of the stud 76 gives a certain guidingfunction to the hole 77. By means of the lateral support of the stud 76to the edge portion of the hole 77, the upper portions of the means isto a great extent unloaded from bending moment being generated by thedynamic forces of the flow.

According to this second embodiment, the blocking means is also providedwith an upper sealing device 78 which is shown in FIG. 12 and on alarger scale in FIG. 14. The sealing device 78 consists of a sealingring 79 in the form of an upside-down lid with a cylindricallydownwardly protruding wall portion 80 and, for example, a plane gableportion 81. The lid is axially moveable against the action of a springdevice 82. In the shown example, it consists of a number of, for examplefour, compression springs in the form of helical springs 83 with onescrew each 84 acting as guiding and abutment. The screws 84 extendthrough holes 85 in the gable portion 81 of the sealing ring 79 and arefastened to a fixed upper portion 86 of the body of the blocking means.

In the embodiment according to FIG. 12, the elastic cover 51 extendsinside of the sealing ring 78 which thereby is sealingly maintainedagainst the upper portion 86 of the body. Through the action of thespring device 82, the vertical position of the sealing ring in relationto the body is adapted to the outer diameter of the pipeline 57, whichby means of this may vary within certain tolerances.

In the modified embodiment according to FIG. 14, the elastic cover 51extends on the outside of the sealing ring 79, by means of which aparticularly tight seal is obtained due to the fact that the circularlyextending edge portion 87 of the sealing ring presses a portion of theelastic cover 51 against the edge portion 88 of the hole 56. In thisregard, two O-rings 89 assure a seal between the inside of the sealingring 79 and the upper portion 86 of the body. A sealing ring 90 with asupporting flange 91 locks the elastic cover 51 in its upper portion sothat it will not be brought downwardly. The locking ring 90 alsoprovides support and takes up a bending moment due to loads originatingfrom the flow in the pipeline.

FIG. 13 shows the clamp 1 in a second embodiment, adapted to theblocking means 74 according to FIG. 12. The difference to the partaccording to FIG. 1 is that its abutment member 8 is, at its lowerportion opposite the opening 12, provided with a bowl-shaped portion 92which for example is cylindrical with a diameter which slightly exceedsthe diameter of the drill bit 71. In this manner, it is permitted duringsawing that the drill bit 71 be lowered into the part 92, which may alsoaccomodate the sawn-out portion of the pipeline, unless it is not caughtand carried away by the drill bit when this is removed. Around thehole-shaped portion 92 on the inside of the abutment portion 8, there isarranged a seal 93 which extends circularly, which is also the case atthe opening 14 of the portion.

The invention is not limited to the embodiments which have beendescribed above and in the drawings, but may be varied within the scopeof the appended claims. For example, the clamp 1 may be shaped with athin support loop which forms a means for holding on during the makingof holes and during blocking. However, a seal around the locations whereholes have been produced must be assured. The guiding and operation ofthe sliding elements may be carried out in another way.

I claim:
 1. A device for blocking flow in a pipeline under pressure,comprising:(a) a clamp member for encasing a section of a mantle surfaceof the pipeline; (b) a pipe socket with a valve switchable between anopen and closed position; (c) a hole-making tool for producing holes inthe mantle surface during sealing between the tool and the pipe socket,and (d) a blocking assembly for inserting through the produced hole andfor expanding in the pipeline for the purpose of blocking flow in thepipeline, said blocking assembly comprising(1) a body having across-sectional dimension less than the cross sectional dimension of thehole; (2) a support member guided in said pipe socket for supportingsaid body, said support member having an operating element rotatablymounted therein; (3) two sliding elements carried for reciprocatingmotion by guides in said body; and (4) a transmission gear comprisingtwo rack means cooperatively associated with respective slidingelements, and at least one gear mounted in said body and engaged withsaid rack means for transmitting rotary motion of said operating elementto reciprocating motion of said sliding elements in opposite respectivedirections between an open position, in which said sliding elements areretracted into said body, and an expanded position, in which saidsliding elements extend from said body, causing a portion of saidsliding elements to create a seal with an inner surface of the pipelineto substantially block flow therethrough.
 2. A device as claimed inclaim 1, wherein said pipe socket comprises:an inner part; and andouter, releasable part with an outer opening for sealingly inserting adrive shaft of the hole-making tool during the hole-making stage andsealingly inserting the support member of the blocking assembly; whereinsaid valve is located between said inner and outer parts of said pipesocket and is adapted to seal said inner part when said outer part isremoved or is opened.
 3. A device as claimed in claim 2, furthercomprising::a driving device; and a driving device support attached tosaid outer portion of said pipe socket for supporting said drivingdevice, whereby a rotary output shaft of said driving device is on alongitudinal axis of said pipe socket, and said driving device ismovable to various positions along said longitudinal axis.
 4. A deviceas claimed in claim 3, wherein said hole-making tool is releasablyattached to said output shaft of said driving device so that a toolportion of said hole-making tool, in a retracted position, is located insaid outer potion of said pipe socket and, in an advanced position, maybe pressed against the mantle surface of the pipeline.
 5. A device asclaimed in claim 2, wherein said body of said blocking assembly isadapted to be accommodated in said outer portion of said pipe socketwith said closing valve closed, and to be inserted through said closingvalve and through the produced hole in the pipeline with said valvebeing open, said body further adapted to make contact with the innercircumference of the pipeline.
 6. A device as claimed in claim 1,wherein at least a portion of said sliding elements, when in saidexpanded position, are covered by an elastic, highly expandable sealingcover for sealing against said inner surface of said pipeline.
 7. Adevice as claimed in claim 1, wherein said support member comprises aposition control means and a shaft sleeve fixed to said body which isadapted, by said position control means, to establish a rotary positionof said body in relation to the pipeline.
 8. A device as claimed inclaim 1, wherein a lower part of said blocking assembly is provided witha lower support stud adapted to be inserted into a second produced holein the pipeline and to form a support against an edge portion of saidsecond produced hole to support said blocking assembly against a bendingmoment created by the pressure in the pipeline, said second hole beingpositioned in front of and opposite the first hole.
 9. A device asclaimed in claim 8, wherein at least a portion of said sliding elements,when in said expanded position, are covered by an elastic cover forsealing against said inner surface of said pipeline, and wherein saidlower support stud protrudes through a hole in said elastic cover.
 10. Adevice as claimed in claim 9, wherein said stud is conical andexternally tapered.
 11. A device as claimed in claim 8, wherein saidclamp member comprises a bowl-shaped space for allowing insertion ofsaid hole-making tool in order to produce the second hole.
 12. A deviceas claimed in claim 1, wherein said blocking assembly comprises an uppersealing device for sealing around the produced hole, said sealing devicecomprising a lid having a downwardly protruding collar and a springdevice for urging said lip to an operating position against an edgeportion of the hole.
 13. A device for blocking flow in a pipeline underpressure, comprising:(a) a clamp member for encasing a section of amantle surface of pipeline; (b) a pipe socket with a valve switchablebetween an open and closed position; (c) a hole-making tool forproducing first and second holes in the mantle surface during sealingbetween the tool and the pipe socket, said second hole being positionedin front of and opposite said first hole; and (d) a blocking assemblyfor inserting through the first produced hole and for expanding in thepipeline for the purpose of blocking flow in the pipeline, said blockingelement comprising(1) a body having a cross-sectional dimension lessthan the cross sectional dimension of the first produced hole; (2) asupport member guided in said pipe socket; (3) two sliding elementscarried by said body, said sliding elements being adjustable fromoutside the device through said support member between an open position,in which they are retracted into said body, and an expanded position, inwhich said sliding elements extend from said body, causing a portion ofsaid sliding elements to create a seal with the inner surface of thepipeline to substantially block flow therethrough; and (4) a lowersupport stud provided in a lower part of said blocking means adapted tobe inserted into said second produced hole and to form a support againstan edge portion of the second produced hole to support said blockingassembly against a bending moment created by the pressure in thepipeline.
 14. A device as claimed in claim 3, wherein said slidingelements arc covered by an elastic cover, and wherein said lower supportstud protrudes through a hole in said elastic cover.
 15. A device asclaimed in claim 14, wherein said stud is conical and externallytapered.
 16. A device as claimed in claim 13, wherein said clamp membercomprises a bowl-shaped space for allowing insertion of said hole-makingtool in order to produce the second hole.